I'm trying to union a large number of csv files together in Desktop 2018.

The problem I'm running into is that a few of the files have the column headers, but the majority do not. Which means tableau is trying to use the first row of data as column names, adding a host of 'additional' columns to the union.

Is it possible to have Desktop or Prep effectively union based on the position of columns rather than column header names? Is there some alternative to changing all the files?